Smithsonian / USGS Weekly Volcanic Activity Report 11-17 March 2015
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Smithsonian / USGS Weekly Volcanic Activity Report
11-17 March 2015
Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx)
URL: http://www.volcano.si.edu/reports_weekly.cfm
New Activity/Unrest: Fuego, Guatemala | Popocatepetl, Mexico | Ruang, Sangihe Islands (Indonesia) | Turrialba, Costa Rica | Ubinas, Peru
Ongoing Activity: Aira, Kyushu (Japan) | Asosan, Kyushu (Japan) | Chirpoi, Kuril Islands (Russia) | Colima, Mexico | Dukono, Halmahera (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Klyuchevskoy, Central Kamchatka (Russia) | Manam, Papua New Guinea | Reventador, Ecuador | Sheveluch, Central Kamchatka (Russia) | Shishaldin, Fox Islands (USA) | Zhupanovsky, Eastern Kamchatka (Russia)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
Fuego | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m
INSIVUMEH reported that during 10-11 March the magnitude and number of explosions at Fuego increased, producing ash plumes that rose 650-950 m above the crater and drifted 12 km W, NW, and N. Shock waves from explosions were detected in nearby areas including Panimache I and II (8 km SW), Morelia (9 km SW), Sangre de Cristo (8 km WSW), and San Pedro Yepocapa (8 km NW). During 12-13 March explosions generated ash plumes that rose 800 m and drifted 10-12 km S and SW. Incandescent tephra was ejected 100 m high. During 15-16 March ash plumes from explosions rose 550-950 m and drifted 10-12 km WSW; shock waves were reported and ash fell in Panimache, Morelia, and Santa Sofía (12 km SW).
Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3763-m-high Fuego and its twin volcano to the north, Acatenango. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at Acatenango. In contrast to the mostly andesitic Acatenango, eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/
Popocatepetl | Mexico | 19.023°N, 98.622°W | Summit elev. 5426 m
CENAPRED reported that during 10-17 March the seismic network at Popocatépetl recorded between 6 and 100 gas-and-steam emissions that likely contained some ash; cloud cover mostly prevented observations of the volcano, so on most days ash in the plumes was not confirmed. Two explosions at 1047 on 10 March generated ash plumes that rose 1.5 km above the crater. An explosion on 11 March produced a plume that rose 1 km. The Alert Level remained at Yellow, Phase Two.
Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 CE, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since precolumbian time.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/
Ruang | Sangihe Islands (Indonesia) | 2.3°N, 125.37°E | Summit elev. 725 m
PVMBG reported that emissions from Ruang were unobserved during periods of clear weather from 1 January through 12 March. Seismicity increased starting on 6 March prompting PVMBG to raise the Alert Level to 2 (on a scale of 1-4) on 12 March. Residents and tourists were warned not to approach the craters within a 1.5-km radius.
Geologic Summary. Ruang volcano, not to be confused with the better known Raung volcano on Java, is the southernmost volcano in the Sangihe Island arc, north of Sulawesi Island. The 4 x 5 km island volcano rises to 725 m across a narrow strait SW of the larger Tagulandang Island. The summit of Ruang volcano contains a crater partially filled by a lava dome initially emplaced in 1904. Explosive eruptions recorded since 1808 have often been accompanied by lava dome formation and pyroclastic flows that have damaged inhabited areas.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://www.vsi.esdm.go.id/
Turrialba | Costa Rica | 10.025°N, 83.767°W | Summit elev. 3340 m
Based on webcam views, weather models, and OVSICORI-UNA updates, the Washington VAAC reported that on 8 March diffuse ash emissions rose from Turrialba's West Crater and seismicity increased. OVSICORI-UNA reported an ash emission at 0100 on 11 March. Another ash emission occurred at 1050 on 12 March. Almost continuous ash emissions were observed in the afternoon and were punctuated by two noticeable explosions at 1338 and 1450. Ash plumes rose as high as 2 km above the crater and drifted NW. Ashfall occurred in the Central Valley and in the capital of San Jose (30 km WSW), and caused the closure of the Juan Santamaria International Airport, 48 km W, which reopened during the evening on 13 March. The local Tobias Bolanos airport (40 km WSW) closed intermittently. On 13 March two short explosions occurred at 1045 and 1100, and then a third occurred at 2100. According to the VAAC, ash plumes that day drifted 45 km NE at an altitude of 9.1 km (30,000) a.s.l. and drifted over 35 km W at an altitude of 6.1 km (20,000 ft) a.s.l.
Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive 3340-m-high Turrialba is exceeded in height only by Irazú, covers an area of 500 sq km, and is one of Costa Rica's most voluminous volcanoes. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.
Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/;
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html; Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE) http://www.cne.go.cr/
Ubinas | Peru | 16.355°S, 70.903°W | Summit elev. 5672 m
Instituto Geofísico del Perú (IGP) Observatorio Volcanológico del Sur (OVS) reported that during 10 February-17 March seismicity at Ubinas was generally low, although a hybrid event was detected on 11 March. Two main sources of seismicity were located 1 km W of the crater at depths of 1-3 km and 2 km NW at depths of 1-5 km. Water-vapor emissions rose as high as 1.5 km above the crater. Sporadic ash emissions were observed on 17 March.
Geologic Summary. A small, 1.4-km-wide caldera cuts the top of Ubinas, Peru's most active volcano, giving it a truncated appearance. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Perú. The growth and destruction of Ubinas I was followed by construction of Ubinas II beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.
Source: Instituto Geofísico del Perú (IGP) http://www.igp.gob.pe/
Ongoing Activity
Aira | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m
JMA reported that 10 explosions from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 1,300 m during 13-16 March. Incandescence from the crater was periodically visible at night, and inflation continued to be detected. The Alert Level remained at 3 (on a scale of 1-5). Based on JMA notices, the Tokyo VAAC reported that during 11-17 March plumes rose to altitudes of 1.8-4.3 km (6,000-14,000 ft) a.s.l. and drifted SE, E, and N.
Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Sources: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/;
Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html
Asosan | Kyushu (Japan) | 32.884°N, 131.104°E | Summit elev. 1592 m
JMA reported that, based on seismic data, the eruption from Asosan’s Nakadake Crater that began on 25 November 2014 continued during 13-16 March. High-amplitude tremor continued, although it had decreased on 9 March. The Alert Level remained at 2 (on a scale of 1-5).
Geologic Summary. The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Nakadake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.
Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/
Chirpoi | Kuril Islands (Russia) | 46.525°N, 150.875°E | Summit elev. 742 m
SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 9, 14, and 15 March. Cloud cover obscured views on other days during 9-16 March. The Aviation Color Code remained at Yellow.
Geologic Summary. Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.
Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/?id_d=659
Colima | Mexico | 19.514°N, 103.62°W | Summit elev. 3850 m
Based on satellite images, Mexico City MWO, Colima Tower notices, and a webcam, the Washington VAAC reported ash plumes from Colima during 11-13 March. On 12 March an ash cloud observed in satellite images was located between 40 and 90 km ENE. Additional emissions produced ash plumes that drifted 50-90 km ENE. Later that day ash plumes rose to altitudes of 6.1-6.7 km (20,000-22,000 ft) a.s.l. and drifted E, ESE, and SE. On 13 March an ash plume rose to an altitude below 4.9 km (16,000 ft) a.s.l. and drifted E. Thermal anomalies were detected during 12-13 March.
Geologic Summary. The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4320 m high point of the complex) on the north and the 3850-m-high historically active Volcán de Colima at the south. A group of cinder cones of late-Pleistocene age is located on the floor of the Colima graben west and east of the Colima complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the south, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Dukono | Halmahera (Indonesia) | 1.68°N, 127.88°E | Summit elev. 1335 m
Based on a pilot observation, analyses of satellite imagery, and wind data, the Darwin VAAC reported that on 13 March an ash plume from Dukono rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted 55 km ENE.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
Karymsky | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m
KVERT reported that during 6-13 March moderate activity at Karymsky continued. Satellite images showed ash deposits extending in different directions and a thermal anomaly on the volcano on 7 March. The Aviation Color Code remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m
During 11-17 March HVO reported that Kilauea’s 27 June NE-trending lava flow continued to be active with several small and scattered breakouts within the flow-field margins, upslope of the leading front. Most of the erupting lava was found in the two largest breakouts: the 21 February breakout on the flank of Pu'u 'O'o and the 9 March breakout near the forested cone of Kahauale'a. A third and relatively small breakout was 5 km farther NE of Pu'u 'O'o. At Pu'u 'O'o Crater, glow emanated from several outgassing openings in the crater floor. A small lava pond was visible in the S portion of the crater. The circulating lava lake occasionally rose and fell in the deep pit within Halema'uma'u Crater. Gas emissions remained elevated. During 12-13 March a tiny lava flow erupted from the NE edge of the crater.
Geologic Summary. Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
Klyuchevskoy | Central Kamchatka (Russia) | 56.056°N, 160.642°E | Summit elev. 4754 m
After a quiet period of 24 hours at Klyuchevskoy, volcanic-tremor magnitude significantly increased at 0500 on 10 March prompting KVERT to raise the Aviation Color Code to Orange. Video images showed moderate gas-and-steam activity while satellite images detected a gas-and-steam plume with small amounts of ash drifting about 92 km ESE at an altitude of 5 km (16,400 ft) a.s.l. During 10-11 March a weak thermal anomaly over the summit was detected.
Geologic Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Manam | Papua New Guinea | 4.08°S, 145.037°E | Summit elev. 1807 m
RVO reported that activity at both Manam's Southern Crater and Main Crater was low during 1-18 March although inclement weather made crater observations difficult; no noises were reported. Seismicity had slowly and erratically increased since 28 February, peaked on 13 March and remained at that level through 15 March, and then increased again through 18 March. The seismicity was characterized by small-to-moderate, sub-continuous, and continuous volcanic tremor. Discrete low-frequency earthquakes were also recorded.
Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys" channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.
Source: Rabaul Volcano Observatory (RVO)
Reventador | Ecuador | 0.077°S, 77.656°W | Summit elev. 3562 m
During 10-17 March IG reported moderate seismic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador; cloud cover often prevented visual observations. A lava flow continued to descend the SW flank and was 1.2 m long by 13 March.
Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m
KVERT reported that during 6-13 March lava-dome extrusion onto Sheveluch’s N flank was accompanied by incandescence, hot block avalanches, and fumarolic activity. Strong explosions on 8 March generated ash plumes that rose to altitudes of 7-8 km (23,000-26,200 ft) a.s.l. and drifted 885 km E. A daily thermal anomaly was visible in satellite images. The Aviation Color Code remained at Orange.
Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Shishaldin | Fox Islands (USA) | 54.756°N, 163.97°W | Summit elev. 2857 m
AVO reported that seismicity at Shishaldin continued to be elevated over background levels during 11-17 March, indicating that low-level eruptive activity confined to the summit crater likely continued. Minor steaming from the summit was observed in webcam images on 11 March. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Geologic Summary. The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.
Source: US Geological Survey Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
Zhupanovsky | Eastern Kamchatka (Russia) | 53.589°N, 159.15°E | Summit elev. 2899 m
KVERT reported that a moderate explosive eruption at Zhupanovsky continued during 6-13 March. Two strong explosions on 7 and 8 March generated ash plumes that rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. Satellite images detected ash plumes drifting 333 km E on 7 and 10 March, and 232 km NE on 8 March. A thermal anomaly was also detected during 7-10 March. The Aviation Color Code remained at Orange.
Geologic Summary. The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated volcanic complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene, the fourth is Holocene in age and was the source of all of Zhupanovsky's historical eruptions. An early Holocene stage of frequent moderate and weak eruptions from 7000 to 5000 years before present (BP) was succeeded by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 years BP. Historical eruptions have consisted of relatively minor explosions from the third cone.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
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